Naked Trees and Winter Twigs

Families and students explore the lives of winter trees in the Ecosystem Preserve.

The snow-covered pond outside Jeanette Henderson’s office in Calvin College’s Bunker Interpretive Center is surrounded by a forest of bare trees. Within a few minutes, the tree outside Henderson’s window is filled with mourning doves.

Henderson, program manager at the Bunker Interpretive Center, is busy planning this year’s inaugural event in the First Saturdays at the Ecosystem Preserve series. “Naked Trees and Winter Twigs,” scheduled to begin at 10 a.m. on Feb. 5, is one of many educational events offered to the public free-of-charge.

The upcoming program will introduce children and parents to the hidden life of Michigan’s snowbound trees. Henderson gestured to the woods across the pond. “‘Do trees freeze in the winter?’ Kids ask that question,” she said. “How do they survive? Why don’t they die? What’s the magic that happens where every spring we get leaves and flowers?”

Smelling the trees

Participants in “Naked Trees and Winter Twigs” will learn how to identify trees by sight, feel, and smell. Henderson explained: “When you’re outside exploring nature, it’s not one-dimensional. You’re using all your senses.” The program will address “all the questions a five year-old asks [about nature]… We’re going to look at the big, fat buds on the twigs and last year’s leaf petiole … the scar where the leaf fell off … You can break open a twig, and certain twigs like black cherry have a sweet smell to them. Others, like sassafras, smell like lemon.”

Henderson believes First Saturdays programs offer families an opportunity to instill a passion for nature in their children. “If you can start young with families … ,” Henderson said, “they are much more likely to engage in stewardship activities. That’s why those programs exist. It’s developing an appreciation and a wonder for God’s creation.”

First Saturdays programs are one manifestation of the Bunker’s role as a resource for the community. “January Series we tout as our gift to the community. Well, this is our unsung gift to the community,” Henderson said. “There are a lot of people that live in the neighborhoods that use the preserve … . [It] is open dawn to dusk, 365 days of the year.”

At the Bunker, Calvin students and neighbors from the community view creation through the prisms of both art and science, Henderson said: “A lot of artists are inspired by the natural world, and… many naturalists are inspired by how artists render the natural world.” The Bunker’s staff incorporates both elements into the First Saturdays programs. In addition to learning how dormant trees store water, for example, attendees will create collages out of twigs taken from the preserve’s beech-maple forest.

Bunker academics

This dual approach to environmental education extends to Calvin’s academic programs. Professor Frank Speyers led “An Introduction to Plein Air Painting” from the Bunker last January, a class in which students drew aesthetic inspiration from the wintery landscapes of the Ecosystem Preserve.

This interim, Professor Keith Grasman used the Bunker as ahome base for his “Winter Ecology” class.

“We make extensive use of this facility because of its location on the Ecosystem Preserve,” Grasman said. “One of the major questions [the class addressed] was ‘How do different plants and animals and other organisms deal with the winter environment?... How do different plants cope with freezing temperatures?’”

To answer this question, the students in Grasman’s class collected twigs of different ages, species and habitats, inserting highly sensitive thermal couplings into tiny holes drilled into the wood. The twigs were placed into containers filled with liquid nitrogen vapors. Students then tracked the temperature changes within the twigs minute-by-minute, watching for signs of cell death. The purpose was to discover which trees are able to withstand the coldest temperatures.

The balsam fir, studied by seniors Anna Kim and Nicole Swierenga, was able to endure temperatures as cold as -80°C.

Beauty of creation

Swierenga finished her career at Calvin with “Winter Ecology.” “I saw lots of creation's beauty this interim … ,” she said. “We were able to see many different animal tracks and birds flying around while taking our observations. It was really cool to see so much life in the winter season.”

Kim and Swierenga also studied two bird species native to the preserve, the black-capped chickadee and the tufted titmouse. Kim said, “Birds have to feed constantly throughout the day to compensate for the energy lost to the cold. They're not really able to store up fat [or] food… to prepare for the winter and have to rely on God that they will be able to find [the food] they need for the hour, even for the minute. I found this relationship [between] the creator and the creation to be very beautiful.”

This year, the Ecosystem Preserve is celebrating its 25th anniversary. A gift from Helen Bunker, a longtime friend of Calvin, along with grants from the Grand Rapids Community Foundation and the Frey Foundation and Thelma Venema, initiated the construction in 2003 of the Bunker Interpretive Center, the first LEED-certified building on campus.